Soluble casein



Feb.7, i933 ALBERT F. O. 'GEBHANN, OF CLEVELAND, OHIO, ASSIGNOR TO 8. 1H. A. CORPORATION, OF CLEVELAND, OHIO, A CORPORATION OF OHIO SOLUBLE CASEIN E Drawing. Application filed December 19, 1929. Serial No. 415,859.

This invention relates to milk products, in ice cream, in addition to which alkaline and more 1particularly to the protein concaseinate solutions have more or less of an tent thereo especially the casein. The obobjectionable soapy taste that at times heject of the invention is to provide an imcomes disagreeably pronounced.

5 proved and soluble form of casein available For the foregoing and other'reasons, as 65 forvarious commercial uses and capable of well as'to secure a less viscous mixture which production in large quantities at low cost is more readily handled, it is desirable toproand by. ordinary methods, and which form vide an improved soluble form of casein not of casein also has lower or reduced viscosity hitherto recognized as available for use, and.

as compared with prior forms of casein, my invention aims to provide such a mate- 60 whereby, for certain uses, it is preferable to Hal.

the more viscous forms and is more satisfac- At first blush, disregarding the question of tory from various standpoints in the manu- Viscosity and following precedent,- it would facture of ice cream and other edible prodseem to be clear that soluble casein may only ucts. Although the invention is useful in be formed by the production of an alkaline o5 connection with casein prepared for indussolution, elther a fixed alkaline solution utitrial uses such as for plastics, glue, paints, lizing the h dra-tes or salts of magnesium, paper size, etc., it finds greater utility in the alclumor t e l1ke, or a volatile-alkali soluhigher quality carefully prepared edible tlon, such as ammonia and water, or solutions casein products, but is not limited thereto. 0f a ky a m s, such P methylamlne. HOW- It is well recognized that casein is relativeever, there are certain ob ect1ons to the use ly insoluble in water unless peptized or made of x d alkaline sp wns, 119h as then high soluble in some alkaline form. Gortner ash content and higher viscosity, and experi- (page 14, Casein and its industrial applicaence W1th' VOla tlle- -a lka,l1 solutions does not E tions, published 1927 by the Chemical Cata ggestthelrsmtablhtyforthepurposes. For

log 00., Inc, New York) says of it; exam le, a volatile-alkali solution of case n It reacts as a weak acid, is insoluble in ma 8 prepared by suitably treating casein water, alcohol and other neutral organic W1 ammonla, bu soluble ammonlum casesolvents, and readily soluble in water 'cona W n xp s d 9 1 10 6s m0St 0f '1t8 30 tainin the hydroxides-or the carbonates of ammonia-and usually reverts to the origmal the algali or alkaline earth metals, insoluble casein, in add tion to which a solu- Some of the alkaline caseinates, such as iOll f flmm pll m caselnate 111 water, when sodium caseinate, have ben applied to vari- PQ ed to all, los s th w ter and am.- ous industrial uses, such as for an in edimonla, usually again resulting in the depo-' 35 m; f an i cream i (Z ll t nt sitionof the original nsoluble case n. 86 1,598,033, patented August 31, 192 the Su h actlon on h p b vqlatlle-alkah purpose being to control the overrun or swell casemates has led to the expectation that dry: of th i int i i a it bl mg of a volatile-alkali casemate should alsurface tension of the mix. Nevertheless, alw ys Pro ce th Well known Insoluble form kaline caseinates for this purpose, as well as f sem. Strange to say, expenence has 90 for other purposes, have not been wholly sa't Shown that the 1s not umversall true. ric I isfactory, one reason being-the objectionto ng What are th condltlons during their high viscosity, by reason of which it is h drymg operatlon, the eflect of drying .1

' difiicult to make up solutions thereof onv a volatile.-alkali easeinates, such as ammonium 45 factory scale because of the great tendency caseinate, by ordinary processes, such as by of the material to swell when in contact exposure to air'or in a vacuum pan, is quite with. water, forming clots or lumps which indeterminate, 'roducing a more or less inam dificultto break down by mixing, which soluble or solub e product. More often than very materially interferes with proper mixnot the caseinate may revert to the former ture and solution when the material is used insoluble form. However, when it is reduced ;diti on,s, such as with extremelra "while In a state'of very fine sub 1v1s1on, asoccurs 1n an ordinary spray drier orpowder by spray drying,

was proved not to be the case,

to dryness under special andk definite conidity and mill the product is uniformly very highly soluble, with solubility ofv the same order or degree as sodium caseinate, in addition to which the viscosity may be decreased and 1115 material has other advantageous prop- In other words, I have discovered that by dissolving casein by the use of a volatile a kali, such as ammonia, by proper treatment. and then removing the'water and ammonia or other volatile solvent ver rapidly while the material is very finely ivided, such as no opportunity is afforded for h drolysis or chemical action internal to the roplets or fine particles, and the prodnot to all intents and purposes uniformly retains the solubilit in water of the volatilealkali caseinate rom which it is formed. Therefore, soluble casein not only is capable of production with certainty on a large scale by present day'practical and commercial processes, but also it is produced in a form which is useful in all places where fixed alkali caseinates or other soluble forms of casein have heretofore been employed, in addition to which the improved material may have reduced viscosity, and its solution has no objectionable soapy taste, so that for many purposes, such as for use in an we cream mix, it is far superior to the fixed alkali caseinates, such as sodium caseinate.

Practice and experience with the material have led to certain impressions, although what actually occurs is by no means certain.

At first it was thought that the extremely high-solubility might bedue to failure to com letely remove the ammonia by the spray drying or evaporating step. That, however,

because careful analysis of many samplesv casein prepared by spray drying ammonium caseinate showed a lower ammonia content than ordinaril is found either in ammonium caseinate whic has been permitted to stand exposed for a long time, or in casein or casein roducts prepared by other processes than with the use of ammonia. For example, two samples of spray dried ammonium caseinate with a solubility averaging about 86% were found to contain respectively .0051% and .127 5% of ammonia, whereas two samples of ammonium caseinate prepared by exposing 20 mesh ground casein to ammonia gas under pressure and storing for over a year, one in an air tight can and the other in a closed paper bag, were found to contain respectivcly .68% and 18% ammonia. Indeed, sodium caseinate may and usually is found to contain a hi her percentage 0 ammonia than was found in the samples of spray dried ammonium caseinate referred to.

ing the -m aterial,-the individual dro of the soluble 4 The'most reasonable explanation is that the high solubility, as well as the low viscosity, may be accounted for by-the extremely high state of "division of the casein particles resulting from spray drying. By spra drypi ets of ammonium caseinate solutionata concentration' of 10% or 15% total solids lose both water and ammonia in the heated atmosphere of the powder mill so rapidly that there is no time for chemical changes, such as hydrolysis, to occurin the casein molecule. The water and ammonia vaporize so rapidly as to presumably form tiny bubbles with1n the smalldroplets, leaving finally onl the nonvolatile casein in the form of thin lms. The

resulting powder formed from a collection to have more or less the property of colloids.

Moreover, this form of casein is probably so soluble that solution occurs without material swellin of the casein films, as distinguished from t e appreciable swelling which takes place when solution is produced by the use of an alkali.

That the solubility of this form of casein is probably due to its physical rather than to its chemical condition-is evidenced by the fact that microscopic examination of a sample of the product has disclosed a more or less hollow shell-like structure, the particles being. somewhat like broken 1 e gshells. Moreover, some ofthis spray-dri soluble .casein has been dissolved in water and found to be completely soluble, and the solution thereof has been dried by other processes than spra 'dr'yin such as by permittin a film of mi; mateial to dry in the open air on a glass plate. Microscopic examination of such dried film has a characteristic form resem ling broken eggshells, leading to the supposition that instead of a true solution, the mixture of this mate-' rial with water produces a colloidal dispersion equivalent to, solution. However, while colloidal principles are sug ested as a possible ex lanation of the behavior of the material, I 0 not wish to be understood as offering such suggestions with any certainty of-technical accuracy, and solubility herein should be understood as meaning not only ordinary solubility according to the theory of solutions, but also colloidal dispersions or other equivalents therefor.

From the standpoint of solubility, casein made according to my invention is substantially completely soluble when fresh, with its solubility decreasing slightly with age over a long period. Solubility determinations have been made by shaking a weighed quantity of the material in water at 100 for a definite t'ime, saythirty minutes, film disclosed the nae aaoo tering, evaporating the filtrate dryness,

and comparing the weight of the dried resi--' due with the weight attempted to be dissolved. By such determinations, my casein is 100% soluble when fresh, and a sample six'months old was found to have lost 3.4% solubility.

As to viscosity, my improved casein also may be uniformly less viscous than a high quality carefully prepared edible sodium caseinate, the difference between them in relative viscosity increasing with the concentration, but such difference in viscosity is not essential, as it depends in large measure upon the manner in which the material is used, the strength of the solution, etc. By a series of tests with a Stormer viscosim'eter, relative viscosities of the two materials at different concentrations were obtained as follows:

Concen- Sodium &3; tratlop caseinate mu Per cent Every figure in the above table is the average of ten readings. It will be observed that at the lower concentrations the relative viscosities of the two materials were much'alike, but with the spray dried casein a little less than the sodium caseinate, but in the higher concentrations the difference in relative viscosity was quite marked.

Of course, casein prepared by my method differs from sodium and like soluble caseinates in a number of respects, the chief one of which is that it contains no added fixed ba'se, because it is preferably produced by recipitation from milk by a method which, if anything, tends to reduce rather than to increase the fixed base, usually included in analyses with the ash content. Acid preci itation is therefore preferable, because of t e low ash content due to separation of the calcium originally present in the natural milk; Porcher (Chimie & Industrie, Vol. 19, No. 4, April, 1928) says Casein exists in milk in the form of the caseinate of calcium which is combined with calcium phosphate to form what I have called the complex calcium caseinate plus calcium phosphate. It is well recognized that acid recipitation of casein, carefully accomplishe with properwashin etc., removes a very large proportion 0 the caldium and salts and correspondingly reduces the ash content. When such methods of precipitation are employed,

therefore, or with any methodof casein precipitation which does not increase or which reduces the ash content, the casein prepared by m method not only has no added fixed base, 'ut is more or less free of fixed base, due to the method of preparation. The only alkali involved in its preparation is the amis first separated from milk by any suitable well known method, such as acid precipitation, followed by washing, draining and other ste s, to remove albumen, fats, milk sugar, sa ts and other like materials. The casein is then converted to ammonium caseina.te in any suitable manner, either wet or dry, and by the use of either ammonia gas under pressure or a solut1on of ammonia in water. Suflicient water is used to produce the desired degree of concentration, say 10% or 12%, and with the material homogenized so as to be of uniform texture and suitable for treatment, it is spray dried'in an ordinary spray drier, by introducing it in the form of a mist or spray into a current of heated air in a chamber, whereupon the water and most;

of the ammonia are re oved, as described, and the fine dust falls to the floor and is collected and removed, as is usual in all spray drying. The ammonia gas may berecovered in any suitable manner, such as by absorption in acids, or by adsorption on suitable surfaces, to be returned for treatment of further casein. As a result, the ammonia gas, in this method, is more or less a carrier, merely playing the part of a medium to convert the original insoluble casein into soluble volatile-alkali caseinate for the purpose of spray drying the same, but playing no art in the composition of the final product, rom which it is nearly wholly removed. 7

Soluble casein formed according to my invention is particularly usefulin anice cream mix for controlling the overrun, but in proper proportions it has the advantage of decreased viscosity, is more readily handled and may be more thoroughly mixed or incorporatedwith other ingredients-and without liability of formation of clots or lumps than sodium caseinate. It is also useful for many other purposes; indeed, for any where sodium or other soluble caseinate or any soluble form of casein is required or desirable.

Otheradvantages of my invention will be ap arent to those skilled in the art.

at I claim is: 1. A method of preparing soluble casein,

consisting in peptizing casein vwith a suitable 13 vol atile alkali, and removin the volatile alkali and water at a rate an rial so finely divided that internal chemical changes do not take place and the resulting I product has solubility in water of the same order as sodium caseinate.

- 2. The method of producing soluble casein, consisting in peptizing casein with ammonia,

and spray drying the mixture to remove both ammonia and water, leaving soluble casein. 3. A method of the character described,

consisting in treating casein with ammonia and water to roduce a casein solution, spra drying the so ution, collecting the dried residue, recovering the ammonia gas, and utilizing said gas to treat additional'casein.

4. A casein-like product containin no added fixed alkali base and having so ubility in water of the same order as sodium caseinate, the viscosity of a water solution thereof being less than that of a corresponding solution 'of sodium caseinate. v y

In testimony whereof I hereby aflix my signature.

' ALBERT F. O. GERMANN.

with the mate- 

